Rmx 750 Low Buzzing mode when PC is off

[frostyyflakes]

Hey, I recently build a PC and bought a new Rmx 750w. However, I noticed very faint buzzing from the PSU when the PSU is on standby (PC is off but PSU is still on). Granted, this is very faint: I didn't even notice it until I was basically hugging the PSU to my ear (I'll post a video when I can, because it's nowhere near as bad as what others had). Nothing out of the ordinary anywhere else, and even when the PC is on sleep mode the PSU is basically dead silent and I can't hear the slight buzzing. Is this just normal for the PSU? Been looking at other forums and people discussing similar issues but I see conflicting messages or they have much worse issues than I do. I have used other PSUs in the past that didn't buzz when on standby.

 

Edit: Here's a video showcasing the buzz. It's very faint but it's there

[ame]

[/ame] Edited December 22, 2020 by frostyyflakes

[jonnyguru]

So what's the question?

 

Different people are going to have different levels of noise because everyone's load is different when they build their own PCs.

 

It's not like a Dell where they're all the same and Dell can listen to every PSU in every load condition with the same parts in every build and pin point where the noise comes from and how to resolve it.

 

For example: My kid's PC was buzzing at idle. Turned out to be a USB hub plugged into one of the USB ports. Unplug the USB port and the noise goes away. But she needs the USB port because of all of her external devices, so we just deal with it. This is an example of why one person would have a louder noise than another person.

 

As load changes, switching frequency has to change to maintain high efficiency. High efficiency requirement are relatively new, including efficiency at stand by. As customers plug in different things powered during standby: keyboards, mice, hubs, RGB, memory, etc. that load changes, and therefore switching frequency changes and sometimes that frequency drops into an audible range. The lower that frequency, the more likely most people can hear it.

Edited December 22, 2020 by jonnyguru

[frostyyflakes]

So what's the question?

 

Different people are going to have different levels of noise because everyone's load is different when they build their own PCs.

 

It's not like a Dell where they're all the same and Dell can listen to every PSU in every load condition with the same parts in every build and pin point where the noise comes from and how to resolve it.

 

For example: My kid's PC was buzzing at idle. Turned out to be a USB hub plugged into one of the USB ports. Unplug the USB port and the noise goes away. But she needs the USB port because of all of her external devices, so we just deal with it. This is an example of why one person would have a louder noise than another person.

 

As load changes, switching frequency has to change to maintain high efficiency. High efficiency requirement are relatively new, including efficiency at stand by. As customers plug in different things powered during standby: keyboards, mice, hubs, RGB, memory, etc. that load changes, and therefore switching frequency changes and sometimes that frequency drops into an audible range. The lower that frequency, the more likely most people can hear it.

 

Apologies for not making it so clear, edited original post as such to better specify. My question concerns on how the PSU does the buzzing noise when the PC is off but the PSU is on (I thought this state was called standby, correct me if I'm wrong). I was wondering if that was normal for the PSU to keep buzzing like that (I know technically it's still "on", but from other manufactuer PSUs such as EVGA, I've never heard these noises before when the PSU is on but the PC is off. I unplugged my usb headers and such to see if anything connected was the issue, and the noise seems to still persist. Hopefully that makes it more clear.

 

That being said, the information about how plugging in different powered devices can actually make your PSU more audible was interesting. I’ll definitely keep a mental note on that.

Edited December 22, 2020 by frostyyflakes

[jonnyguru]

Got it. Ok.

 

There's a number of items that are still loading the +5VSB while the PSU is "off".

 

Memory and most USB devices are powered during standby. This is how memory timings are saved and things like wake on are allowed to work.

[frostyyflakes]

Got it. Ok.

 

There's a number of items that are still loading the +5VSB while the PSU is "off".

 

Memory and most USB devices are powered during standby. This is how memory timings are saved and things like wake on are allowed to work.

 

Ahh, okay. So even though my PC is off, things like my keyboard and mouse can technically still be on? Though I don’t believe I have anything related to wake on to warrent that (I’m assuming what you mean by wake on is things like using your mouse or keyboard to wake the computer.

 

I will say I do have an XMP loaded onto my memory, so would that be an example like you stated?

 

And based on what you’re saying, it seems that the faint buzzing noise is a result of this? So it’s intended?

Edited December 22, 2020 by frostyyflakes

[jonnyguru]

RAM these days use +5VSB to store settings. That's why RGB RAM stays lit up while the PC is in stand by when people have RGB RAM.

[frostyyflakes]

RAM these days use +5VSB to store settings. That's why RGB RAM stays lit up while the PC is in stand by when people have RGB RAM.

 

So it seems that the buzzing noise from the PSU when the PC is completely off could come from other peripherals or devices still being connected and powered by the 5V? Keep in mind I’m asking when the PC is completely shutdown, not in something like sleep mode, as the buzzing only happens there

Edited December 22, 2020 by frostyyflakes

[jonnyguru]

So it seems that the buzzing noise from the PSU when the PC is completely off could come from other peripherals or devices still being connected and powered by the 5V? Keep in mind I’m asking when the PC is completely shutdown, not in something like sleep mode, as the buzzing only happens there

 

Right. Completely off, there is still power going to components in the PC.

 

Only if you physically switch the PSU off, via the on/off switch, is it truly off (bt I don't recommend that).

 

There is a trick I've used to help curb some of the noise.

 

If you can find "ErP" in your BIOS, set it to DISABLED.

[frostyyflakes]

Right. Completely off, there is still power going to components in the PC.

 

Only if you physically switch the PSU off, via the on/off switch, is it truly off (bt I don't recommend that).

 

There is a trick I've used to help curb some of the noise.

 

If you can find "ErP" in your BIOS, set it to DISABLED.

 

Cool, thank you for clarifying! After just removing cables from the unit I figured that it came from something powering the mobo, I'm assuming it's either from the memory or the USB hub for the RGB.